Dry ice cleaning apparatus for semiconductor wafers and method for cleaning semiconductor wafers

Abstract

An object of the present invention is to provide a dry ice cleaning apparatus for a semiconductor wafer and a method for cleaning a semiconductor wafer that can reduce the amount of particles remaining on the surface of a semiconductor wafer, suppress a decrease of cleaning effects due to ice formation, and continuously and effectively clean a large amount of semiconductor wafers. The present invention provides a dry ice cleaning apparatus for a semiconductor wafer including a cleaning chamber ( 1 ) into which the semiconductor wafers (W) are sequentially carried in and which has an internal space ( 11 ) for cleaning the semiconductor wafers (W), an inject cleaning nozzle ( 5 ) that is disposed in the internal space ( 11 ) of the cleaning chamber ( 1 ) and injects the dry ice (D) toward the cleaning surface of the semiconductor wafer (w), and a transfer robot ( 2 ) that is disposed in the internal space ( 11 ) of the cleaning chamber ( 1 ) and sequentially carries the semiconductor wafers (W) from the outside of the cleaning chamber ( 1 ) into the internal space ( 11 ); and wherein while the transfer robot ( 2 ) holding the semiconductor wafer (W) carried into the internal space ( 11 ) non-horizontally, the inject cleaning nozzle ( 5 ) injects the dry ice (D) onto the semiconductor wafer (W).

The invention claimed is: 
     
         1 . A dry ice cleaning apparatus for semiconductor wafers that removes impurities attached to a cleaning surface of the semiconductor wafers by injecting dry ice onto the semiconductor wafers,
 wherein the dry ice cleaning apparatus comprises:   a cleaning chamber having an internal space configured to sequentially receive the semiconductor wafers for cleaning;   an inject cleaning nozzle that is disposed in the internal space of the cleaning chamber, the inject cleaning nozzle being configured to inject a purifying gas together with the dry ice toward the cleaning surface of at least one of the semiconductor wafers at an injection pressure of the purifying gas in a range from 0.3 MPa to 1.0 MPa; and   a transfer robot that is disposed in the internal space of the cleaning chamber, has a holding section including a back plate configured to hold the at least one semiconductor wafer, and the transfer robot is configured to sequentially carry the semiconductor wafers from the outside of the cleaning chamber into the internal space;   wherein the inject cleaning nozzle is configured to inject the dry ice and the purifying gas onto the at least one semiconductor wafer with the transfer robot holding the at least one semiconductor wafer non-horizontally while bringing an entire back surface of the at least one semiconductor wafer carried into the internal space into close contact with a holding surface of the back plate; and   wherein the holding section is provided with an upper claw and a lower claw arranged to sandwich the at least one semiconductor wafer, and the upper claw and the lower claw are configured to hold a peripheral end of the at least one semiconductor wafer by sandwiching it in an arc shape.   
     
     
         2 . The dry ice cleaning apparatus for semiconductor wafers according to  claim 1 ,
 wherein the transfer robot further comprises an arm portion configured to support the holding section non-horizontally and movably support the holding section in the internal space of the cleaning chamber.   
     
     
         3 . The dry ice cleaning apparatus for semiconductor wafers according to  claim 1 ,
 wherein the transfer robot is configured to hold the at least one semiconductor wafer carried into the internal space at an angle in a range from 0° to 30° or less with respect to the vertical direction so as to hold the at least one semiconductor wafer vertically, or face the cleaning surface of the at least one semiconductor wafer diagonally upward.   
     
     
         4 . The dry ice cleaning apparatus for semiconductor wafers according to  claim 1 ,
 wherein the inject cleaning nozzle is configured to inject the dry ice and the purifying gas at an angle in a range from 0° to 80° with respect to a direction perpendicular onto the cleaning surface of the at least one semiconductor wafer so as to inject the dry ice and the purifying gas perpendicularly to the cleaning surface of the at least one semiconductor wafer, or inject the dry ice and the purifying gas in a direction that is more downward than perpendicular to the cleaning surface of the at least one semiconductor wafer.   
     
     
         5 . The dry ice cleaning apparatus for semiconductor wafers according to  claim 1 ,
 wherein the dry ice cleaning apparatus further comprises a fan filter unit that configured to circulate the purifying gas in the internal space of the cleaning chamber by causing the purifying gas to flow down from the ceiling side to the floor side of the cleaning chamber.   
     
     
         6 . The dry ice cleaning apparatus for semiconductor wafers according to  claim 5 ,
 wherein the purifying gas which is circulated in flow down is high purity nitrogen gas or clean dry air.   
     
     
         7 . A method for cleaning semiconductor wafers to remove impurities attached to the cleaning surface of at least one of the semiconductor wafers by using the dry ice cleaning apparatus for the semiconductor wafers according to  claim 1 , and injecting the dry ice and the purifying gas onto the semiconductor wafer from the inject cleaning nozzle,
 wherein while the at least one semiconductor wafer carried into the internal space of the cleaning chamber is held non-horizontally, the dry ice and the purifying gas are injected from the inject cleaning nozzle onto the semiconductor wafer.